Mounting an electrical box on a block wall frequently requires the installer to form a hole in the opposite side of the wall in order to supply electricity to the newly installed box. Typically the installer uses a hammer, chisel and hammer, or similar tools to make a rough hole in the block and then feeds the electrical cable through the newly formed hole.
Although the aforementioned procedure provides an electrical supply to the electrical box, it is less than optimal as the outer sheath of the electrical cable is in contact with the rough walls edging the hole in the block. This contact between the electrical cable and the rough walls can lead to abrasion of the sheath of the electrical cable and can eventually lead to the cable being shorted out. The rate of abrasion can be particularly severe in those locations where the block wall is subject to considerable vibration, such as in manufacturing locations having rotating or reciprocating equipment mounted nearby.
Electrical boxes for installation on block walls were disclosed in U.S. Pat. No. 6,956,171 and in co-pending U.S. application Ser. Nos. 11/120,707, 11/246,985, 11/185,256, 11/102,392, 11/070,344, 11/009,116, and 10/863,942, all of which are commonly owned by the assignee of the present invention and the contents of which each are referred to herein and incorporated herein in this specification in their entirety. Although several of the electrical boxes disclosed in the aforementioned patents and applications were specifically for mounting on block walls, they did not disclose an improved device or method for feeding electrical cable to the electrical box described therein.
What is needed therefore is an improved device and method for supplying electrical cable an electrical box mounted on a concrete block wall, or similar block wall, that provides a safe electrical supply and minimizes cable abrasion and the chance of electrical shorts.